<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>事件处理</title>
</head>

<body>
  <div id="root">
  </div>
  <script crossorigin src="https://unpkg.com/react@16/umd/react.development.js"></script>
  <script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
  <script src="https://unpkg.com/babel-standalone@6/babel.js"></script>
  <script type="text/babel">

    class Toggle extends React.Component {
      constructor(props) {
        super(props);
        this.state = { isToggleOn: true };

        // 为了在回调中使用 `this`，这个绑定是必不可少的
        this.handleClick = this.handleClick.bind(this);
      }

      handleClick() {
        this.setState(state => ({
          isToggleOn: !state.isToggleOn
        }));
      }
      render() {
        return (
          <button onClick={this.handleClick}>
            {this.state.isToggleOn ? 'ON' : 'OFF'}
          </button>
        );
      }
    }

    ReactDOM.render(
      <Toggle />,
      document.getElementById('root')
    );
  </script>
</body>

</html>